Ch. 4 - Pleural, Pericardial, & Peritoneal Fluids

Question 1

Distinguish between transudative and exudative effusions.

Answer 1

Transudative effusions result from imbalance of hydrostatic and oncotic pressures and have low LDH.

Exudative effusions result from injury (inflammation, cancer, etc) and have high LDH.

Question 2

How do the sensitivity and specificity of pleural and peritoneal sampling perform?

Answer 2

Sensitivity is okay, but specificity is very high.

Question 3

Describe the cytology of benign mesothelial cells.

Answer 3

Isolated or small clusters of large cells with round central nuclei, vacuolated cytoplasm and an outer lacy rim of microvilli.

Question 4

What is the significance of “windows” between mesothelial cells?

Answer 4

They identify clusters as mesothelial rather than glandular.

Question 5

Describe the cytology of histiocytes.

Answer 5

Smaller than mesothelial cells, with often folded nucleus, granular or vacuolated cytoplasm, and no intercellular windows.

Question 6

Distinguish the staining pattern of mesothelium & histiocyte.

Answer 6

Mesothelium: Stains keratin, D240, WT1, calretinin
Histiocytes: Stains CD68, CD163

Question 7

What role does fluid cytology play in transudative effusions?

Answer 7

Almost none; they are indistinguishable by cytology.

Question 8

What defines an eosinophilic effusion? What are its causes?

Answer 8

> 10% eosinophils. Can result from pneumothorax, hemothorax, Churg-Strauss, pulmonary infarction, drugs and infection/parasites.

Question 9

What is the significance of a lymphocytic effusion?

Answer 9

Non-specific, but may herald a nearby malignancy, TB, or recent CABG? Also needs distinguishing from CLL/SLL.

Question 10

Describe the cytology of a rheumatoid pleuritis.

Answer 10

Sparsely cellular sample with granular debris and some macrophages. Distinct lack of mesothelial cells…

Question 11

Describe the cytology of a lupus pleuritis.

Answer 11

“LE cells”, neutrophils or macrophages containing hematoxylin bodies with crescentic nucleus.

Question 12

What are the most common causes of malignant pleural effusion?

Answer 12

Breast, lung, lymphoma/leukemia, GI tract.

In kids, NHL.

Question 13

What are the most common causes of malignant peritoneal effusion?

Answer 13

GYN cancers in general, lymphoma/leukemia, GI tract including pancreatic.

In kids, NHL.

Question 14

What is the clinical significance of a malignant effusion? What can be done?

Answer 14

Portends a poor prognosis, most will survive no longer than 6 months. Consider palliative treatment such as pleurodesis or peritoneovenous shunting.

Question 15

What are the histological types of malignant mesothelioma?

Answer 15

Epithelioid* (includes tubulopapillary, adenomatoid, sheetlike, deciduoid, small cell, and clear cell), sarcomatoid, desmoplastic, and biphasic*.

*will exfoliate in cytology

Question 16

Describe the “mulberry” pattern of mesothelioma cytology.

Answer 16

Large clusters with scalloped edges. Cells are large with prominent nucleolus. N:C ratio may actually be okay.

Question 17

Describe the noncohesive cell pattern of mesothelioma cytology.

Answer 17

No large clusters; individual enlarged cells with prominent nucleoli. Can be quite hard to distinguish from benign.

Question 18

How can reactive mesothelial cells be distinguished from mesothelioma?

Answer 18

Reactive cells should have less clustering and should be smaller. Otherwise can consider EMA staining (positive in noncohesive pattern?) and cytogenetics.

Question 19

How can mesothelioma be distinguished from adenocarcinoma? Include stains.

Answer 19

Adenocarcinoma may have quite different morphology and forms cannonballs (not mulberries). Can send mesothelioma stains (Calretinin, WT1, D2-40) and carcinoma markers (MOC-31, Ber-EP4, specific markers)

Question 20

What is primary effusion lymphoma?

Answer 20

A subtype of DLBCL associated with HHV-8 in HIV+ patients. Often has a null phenotype, and also often EBV+.

Question 21

Describe the cytology of primary effusion lymphoma.

Answer 21

Large plasmablastic or anaplastic cells with large nucleoli and abundant basophilic cytoplasm.

Question 22

What morphologic features of different adenocarcinomas can hint at their origin?

Answer 22

Intracytoplasmic lumina suggest breast. Signet rings suggest stomach. Acinar formations suggest colorectal. Abundant vacuolated cytoplasm suggests clear cell. Prostate tends to be exfoliative.

Question 23

In what conditions can psammoma bodies be seen?

Answer 23

Papillary thyroid carcinoma, lung adenocarcinoma, mesotheliomas, and benign mesothelial proliferations (more often in peritoneum)

Question 24

What sites of origin should stain with PAX-8?

Answer 24

Mullerian (gyne), thyroid, renal, and thymic.

Question 25

Describe the cytology of pseudomyxoma peritonei.

Answer 25

Sparsely cellular specimens with more muciphages than actual lesional cells.

Question 26

How is lobular breast carcinoma identified on cytology?

Answer 26

Very hard to distinguish from histiocytes/mesothelium. Stain for mucin, CEA, GCDFP, mammaglobin, ER/PR.

Question 27

Describe the cytology of squamous cell carcinoma. Does it often spread to cavities?

Answer 27

Cohesive clusters of variably keratinizing cells with dense cytoplasm. No.

Question 28

Describe the cytology of small cell carcinoma. Does it often spread to cavities?

Answer 28

Nuclear molding, high mitotic and apoptotic rates, dark chromatin and inconspicuous nuclei. No.

Question 29

Describe the cytology of melanoma.

Answer 29

Usually isolated large ugly cells with may have melanin pigment. Does not form lacunae on cell blocks.

Question 30

What are some morphologic features of lymphomas that can hint at their subclass?

Answer 30

FL has cleaved and irregular nuclei. LBLs are relatively small with irregular nuclei and scant cytoplasm (hand-mirror?). Burkitt is intermediate and vacuolated.

Question 31

What role does cytology play in CHL?

Answer 31

True malignant effusions are rare; effusions more often result from thoracic duct outlet obstruction.

Question 32

How can ALL and AML be distinguished on morphology?

Answer 32

AML blasts are somewhat larger and may have Auer rods (or at least azurophilic granules). ALL blasts are smaller and may have hand-mirror cytoplasm.

Question 33

What is the significance of cytology in MPNs?

Answer 33

EMH can be seen in pleura or other serosal spaces. Look for megakaryocytes (stain CD61).

Question 34

Describe the cytology of seminoma/dysgerminoma. Does it often involve cavities?

Answer 34

Large uniform noncohesive cells with less cytoplasm than mesothelial cells and with more prominent nucleoli. No.